Looper mechanism for sewing-machines.



N. U. CLARK,-

Patented Jan. 1 1918.

4 SHEETS-SHEET 1.

N. D. CLARK.

LOOPER MECHANISM FOR SEWING MACHINES. APPLICATION HLED DEC. 31. 1914.

Patented Jan. 1, 1918.

v 4 SHEETSSHEET 2 N. 0. ELAHK. LOOPER MECHANISM FOR SEWING MACHINES.

APPLlCATlON FILED DEC. 31] I914- Patented Jan. 1, 1918.

N. D. CLARK.

LOOPER MI'ICHANISM FOR SEWING MACHINES.

APPLICATION FILED DE C. 31.19M-

' Patented Jan. 1, 1918.

4 SHEETSSHEET 4.

M I ,w b .a. 4U- w w M w w a II. w 1 I 1 w T wy %w ...,l M Z. 6. W I 42/ W 549L562 awaa UNITED STATES PATENT OFFICE.

NELSON D. CLARK, OF CHICAGO, ILLINOIS, ASSIGNOR T0 UNION SPECIAL MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

LOOPEB MECHANISM FOR SEWING-MACHINES.

Specification of Letters Patent.

Patented Jan. 1, 1918.

To all whom it may concern:

Be it known that I, NELSON D. CLARK, a citizen of the United States, residing at Chicago, in the county of Cook, State of Illinois, have invented certain new and useful Improvements in Looper Mechanism for Sewing-Machines, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

The invention relates to new and useful improvements in looper mechanisms for sewing machines, and more particularly to a looper mechanism for a sewing machine hav ing a cylindrical work support.

An object of the invention is to provide a looper mechanism for a machine of the above character, wherein said looper may be oscillated into and out of the needle loop in a direction substantially at right angles to the work support and give an extended dwell at the forward end of its stroke.

A further object of the invention is to provide a looper mechanism of the above char acter which may be operated from a cross shaft extending through the standard of the machine in a direction at right angles to the work support.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way of illustration one embodiment of the invention,

Figure 1 is a view partly in side elevation and partly in section, showing a sewing machine embodying my improvements;

Fig. 2 is an enlarged longitudinal sectional view through the work support and a portion of the standard, certain parts being omitted;

Fig. 3 is a view partly in top plan and partly in horizontal section, showing the looper-operating mechanism and also the feed mechanism;

Fig. 4 is a vertical sectional view on the line 44 of Fig. 1;

Fig. 5 is an enlarged detail, showing the means for moving the looper into and out of the needle loop and giving a dwell thereto;

Fig. 6 is an end view showing the looper and the manner of mounting the same on the looper support.

As shown in Fig. 1, my invention is applied to a sewing machine having a standard 1 which carries an overhanging arm 2, at the forward end of which is a needle head. The needle bar 3 reciprocates in said needle head and carries needles 4. A presser bar 5 is carried by the needle head and supports a presser foot 6. The needle bar 3 is reciprocated by the usual needle lever. Also projecting from the standard 1 is a cylindrical bed or work support 7.

In the machine shown in the drawings, the feed of the material is lengthwise of the cylindrical bed. The feedin mechanism comprises a feed dog 8, carried by a feed bar 9. This feed bar 9 at the rear end thereof has a sliding connection with a pin 10 carried by a rocking frame 11. The rocking frame 11 is pivoted at 12. A link 13 adjustably connected to the rocking frame 1s also pivoted at 14 to the feed bar. As the rocking frame is oscillated, this link will reciprocate the feed bar 9 back and forth.

Adjacent the forward end of the feed bar is a bracket 15, which is carried by a sleeve 16 cooperating with an eccentric 17 on the looper shaft 18. As this eccentric 17 oscillates. the forward end of the feed bar will be raised and lowered. These parts are so timed that the feed dog 8 is caused to engage the fabric and feed the same underneath the presser foot. Said feed dog is constructed so as to feed the material up the arm or work support, as shown in the drawings.

Mounted in the standard is the main shaft 19. This main shaft 19 is driven by a suitable belt wheel 20. The main shaft 19 extends in a direction substantially at right angles to the longitudinal axis of the cylindrical bed or work support. The shaft 19 carries an eccentric which operates an eccentric strap 21 and this eccentric strap 21 is attached to the frame 11 and oscillates the same so as to impart the forward and backward movements to the feed bar.

The looper 22 which cooperates with the needles 4 is mounted on the end of the looper shaft 18. The looper is rigidly attached to the shaft and partakes of all the movements of the shaft. Said looper shaft is mounted in a bearing 23 at its forward end, and a bearing 24 adjacent its rear end. Said looper shaft extends beyond the bearing 24 into the standard 1.

On the rear end of the looper sha ft18 is a yoke 25. This yoke may be formed integral with the looper shaft and supports a pivot eccentric strap 36 cooperates.

to the looper.

pin 26. An eccentric 27 is mounted on the main shaft 19 and an eccentric strap 28- .coiiperates therewith. Extending parallel 'with the main'shaft 19 is a cross shaft 29.

A link 31 is connected with the pivot 26 carried by the yoke of the looper shaft, and this link 31 has an adjustable connection with the lower end of the rock frame 30.

Said frame is slotted as at 32, and the stud to which the link31 is connected may be adjusted up and down in said slot, and held in various adjusted positions therein. As this rocking frame is oscillated, it will give to the looper shaft 18 an endwise movement in its bearings, and the extent of this endwise movement may be varied by adjusting the connection of the link 31 with said rock frame, as above noted.

The yoke carries a pivot stud 33 which is eccentrically mounted on the yoke relative to the axis of the looper shaft 18. A bracket 34 is secured to the base of the standard and pivotally supported in said "bracket is arock frame 35. Mounted on the main shaft 19 is an eccentric'with which an This eccentric strap at the lower end connects with a ball stud 37 carried by the outer end of, the

arm 38 in v he rock frame 35. The other arm '39 of the rockframe carries a ball stud 40.

" A link 41 is pivotally connected at one end to the ball stud 40. and at its other end to the pivot stud 33. The link 41 is so proportioned relative to the arm 39, and the rock frame is so timed that the ball stud 40 {will'move substantially into line with the pivotal support of the rock frame 35, and the "pivot stud 33 when the looper is at the forward end of its stroke; and when the looper is' at the rear end of its stroke, this ball stud 40 will beat its extreme throw away from this hollow standard. Said standard rises from a base 1 and the bracket 34 is mounted on this base. Said bracket is slotted as at 34 and the bolts 34 pass through the slots securing the bracket to the base. By loosening these bolts the bracket 34 may be adjusted in a direction at right angles to the axis of the looper shaft and this adjustment permits a slight variation in the dwell given By moving the bracket 34 the-fulcrum of the rock frame 35 is shifted and this will vary the position of the pivotal connection 40 relative to theline passing'ithrough the'ballstud 33 and the fulcrum of the rock frame 35 and thus vary the dwell given to the looper. The link 36 is made in sections and connected by'a' rod 36- which has right and left hand threads thereon so by mounting this bracket on the base of. the

machine, I am able to reduce. the vibration incident to the operation of the parts.

The operation of my improved looper mechanism is as follows: The looper is -moved into and out of the needle loop through the oscillations of the rock frame '35, and is moved laterally for its needleavoiding movements by the rock frame 30. The looper is moved forward to the end of its stroke through the oscillation of the rock frame 35, but when the looper is at the forward end of its stroke the link 41 is moved substantially into line, or perhaps beyond aline joining the pivotal point of the rock frame 35, and the center of the pivot stud 33, and, therefore, said looper will be given an extended dwell while at the forward end of its stroke. The eccentric 27 is so timed as to' give an oscillation to the rock frame 30 at this time, and this will move the looper laterally substantially while it is at a dwell to position the lever for the down stroke of the needles. The looper is then returned to the rear end of its stroke by the return oscillation of therock frame 35 and moved laterally during the return movement by the swinging of the rock frame 30.

The machine above described is especially adapted for covering a seam on very thin material. If the looper thread is given an excessive pull when the looper is at the forward end of its stroke, the fabri is liable to be puckered. By my improved looper mechanis1n,however, wherein the looper is substantially at a dwell at the forward end of its stroke, I am able to avoid unnecessary drawing on the fabric which would result in puckering the same. Furthermore by giving the loope an extended dwell at the forward end of its stroke, I avoid drawing off an excessiveamou'nt of looper thread, which permits the looper thread and needle loops to be quickly drawn up and the setting of the stitch on the downward stroke of the needles.

It is obviousthat minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit o'f'the invention as set forth in the appended claims. l I

- Having thus described my invention, what I cla-im'as-new and desire to secure by Letters Patent, is: l T he combination of see ed a we in lindrical work support carried thereby, a cross-shaft mounted in said standard, means whereby said shaft may be rotated, a looper support extending lengthwise of said cylindrical work support, a looper fixed to said lOoper support, an eccentric carried by said cross shaft, and means operated by said eccentric for moving said looper shaft endwise to give the looper a lateral movement, a second eccentric carried by said cross-shaft, and mean operated thereby for oscillating said looper shaft to move the looper into and out of the needle loop, said last named mean including devices for giving said looper an extended dwell at the forward end of its stroke.

2. The combination of a standard, a cylindrical work support carried thereby, a cross shaft mounted in said standard, means whereby said shaft may be rotated, a looper support extending lengthwise of said cylindrical work support, a looper fixed to said looper support, an eccentric carried by said cross shaft, a swinging frame oscillated by said eccentric, means for connecting said swinging frame to said looper shaft for moving the same endwise, a second eccentric. carried by said cross shaft, a swinging frame operated by said second eccentric, and means operated by said last named swinging frame for oscillating the looper shaft.

3. The combination of a standard, a cylindrical work support carried thereby, a cross shaft mounted in said standard, means whereby said shaft may be rotated, a looper support extending lengthwise of said cylindrical work support, a looper fixed to said looper support, an eccentric carried by said cross shaft, means operated by said eccentric for moving said looper shaft lengthwise, a second eccentric carried by the cross shaft, a swinging frame oscillated by said second eccentric, a link connecting said swinging frame to the looper shaft, said link and the arm of the swinging frame connected thereto being so disposed as to move substantially into line when the looper is at the forward end of its stroke.

4. The combination of a standard, a cylindrical work support carried thereby, a cross shaft mounted in said standard, means whereby said shaft may be rotated, a looper support extending lengthwise of said cylindrical work support, a looper fixed to said looper support, means operated by said cross shaft for moving said looper shaft endwise, an eccentric carried by the said cross shaft, a bracket mounted in said standard, a swinging frame pivoted to said bracket, an eccentric strap cooperating with said eccentric and connected to said swinging frame, said swinging frame having an arm projeoting upwardly therefrom, a link pivoted to the upper end of said arm and connected to said looper shaft, said arm and said link being so disposed as to move substantially into alinement when the looper is at the forward end of its stroke.

5. The combination of a standard, a cylindrical work support carried thereby, a looper shaft mounted in said work support, a looper fixed to the forward end of said shaft, means for oscillating said looper shaft including a rocking frame, means for pivotally supporting said rocking frame on the base of the standard, devices for connecting said rocking frame and said looper support, a main shaft, and means for oscillating said rocking frame from said main shaft, said means for pivotally supporting said rocking frame being adjustable on said base for varying the position of said rocking frame relative to the said devices.

In testimony whereof, I afiix my signature, in the presence of two witnesses.

NELSON D. CLARK.

Witnesses:

HAROLD O. EDWARDS, T. GEORGE TATE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

